Growing concerns over the contributions of billions of tons of annual CO2 emissions from coal-fired power plants and large point sources, as well as other greenhouse gases (GHG), to global climate change have prompted major efforts to curb emissions. A number of diverse technologies, including solvents, membranes, sorbents, and other concepts are currently at various stages of evaluation as potential solutions that can contribute to meeting the challenge of energy efficient carbon capture and storage (CCS). Energy-efficient capture of CO2 is an especially challenging process due to the low concentrations and partial pressures of CO2 typically encountered at power plants and other point sources of CO2 emissions. While membrane-based processes are not as mature as solvent-based technologies for this application, membranes are potentially the most energy efficient option. New membrane materials with unique transport mechanisms are needed to achieve a long-term, energy-efficient technology for capture of CO2 from industrial sources. The compositions and methods disclosed herein address these and other needs.